Early 20th-century psychologist John Watson developed behaviorism as a psychological theory. A leading expert on child-rearing in his time, Watson called for minimal physical contact between parents and children, including no hugging and no lap-sitting. In wildly unethical "Little Albert" experiments circa 1920, Watson used loud noises to condition an infant child to fear rats. He also argued that organizations like the Boy Scouts and YMCA lead to homosexuality, and girls in particular were susceptible because they held hands, kissed, and slept together in the same bed at pajama parties.

Author of books:Behavior: An Introduction to Comparative Psychology (1914)Psychology from the Standpoint of a Behaviorist (1919)Behaviorism (1924)Psychological Care of Infant and Child (1928)The Ways of Behaviorism (1928)